Fix minor typo

data/effects/mask_start_frei0r_alphaspot.xml

 <!DOCTYPE kpartgui>
 <effect LC_NUMERIC="C" tag="mask_start" id="mask_start-frei0r.alphaspot" dependency="frei0r.alphaspot">
         <name>Alpha shapes (Mask)</name>
-        <description>This filter makes a snapshop of the frame before it draws simple shapes into the alpha channel. Use it together with the mask_apply effect, that uses a transition to composite the current frame's image over the snapshot. The typical use case is to add effects in the following sequence: this effect, zero or more effects, mask_apply.</description>
+        <description>This filter makes a snapshot of the frame before it draws simple shapes into the alpha channel. Use it together with the mask_apply effect, that uses a transition to composite the current frame's image over the snapshot. The typical use case is to add effects in the following sequence: this effect, zero or more effects, mask_apply.</description>
         <author>Marko Cebokli, Dan Dennedy</author>
         <parameter type="list" name="filter.Shape" default="0" paramlist="0;0.38;0.62;1">
                 <paramlistdisplay>Rectangle,Ellipse,Triangle,Diamond</paramlistdisplay>

data/effects/mask_start_rotoscoping.xml

 <!DOCTYPE kpartgui>
 <effect tag="mask_start" id="mask_start-rotoscoping" dependency="rotoscoping">
         <name>Rotoscoping (Mask)</name>
-        <description>This filter makes a snapshop of the frame before a keyframable vector based rotoscoping is applied. Use it together with the mask_apply effect, that uses a transition to composite the current frame's image over the snapshot. The typical use case is to add effects in the following sequence: this effect, zero or more effects, mask_apply.</description>
+        <description>This filter makes a snapshot of the frame before a keyframable vector based rotoscoping is applied. Use it together with the mask_apply effect, that uses a transition to composite the current frame's image over the snapshot. The typical use case is to add effects in the following sequence: this effect, zero or more effects, mask_apply.</description>
         <author>Till Theato, Dan Dennedy</author>
         <parameter type="fixed" name="filter" value="rotoscoping">
                 <name>Filter</name>

data/effects/mask_start_shape.xml

 <!DOCTYPE kpartgui>
 <effect tag="mask_start" id="mask_start-shape" dependency="shape">
         <name>Shape Alpha (Mask)</name>
-        <description>This filter makes a snapshop of the frame before an alpha channel (transparency) is created based on another resource. Use it together with the mask_apply effect, that uses a transition to composite the current frame's image over the snapshot. The typical use case is to add effects in the following sequence: this effect, zero or more effects, mask_apply.</description>
+        <description>This filter makes a snapshot of the frame before an alpha channel (transparency) is created based on another resource. Use it together with the mask_apply effect, that uses a transition to composite the current frame's image over the snapshot. The typical use case is to add effects in the following sequence: this effect, zero or more effects, mask_apply.</description>
         <author>Charles Yates, Dan Dennedy</author>
         <parameter type="fixed" name="filter" value="shape">
                 <name>Filter</name>